Conventionally, mirror devices in which mirrors are inclined by an actuator have been known. For example, Patent Document 1 discloses such a mirror device. An actuator in the mirror device is piezo-actuated, and has an actuator body and a piezoelectric element formed on the actuator body.
Such a mirror device is formed by, e.g., formation of a layer on a substrate such as a silicon on insulator (SOI) substrate, or etching of the substrate. For example, Patent Document 1 shows a method of manufacturing a mirror device, the method including forming an insulation layer (for example, an oxide layer) on an SOI substrate, and stacking, on the insulation layer, a lower electrode layer, a piezoelectric layer, and an upper electrode layer which constitute a piezoelectric element. Subsequently, a mask having a predetermined shape is formed and etching is performed, thereby forming the upper electrode layer and the piezoelectric layer into the shape for the piezoelectric element. Then, a portion that will be an actuator body (hereinafter referred to as “a portion to be the actuator body”) including the piezoelectric element, and a portion that will be a mirror (hereinafter referred to as “a portion to be the mirror”) are covered with a resist mask, and the peripheral portion of the portion that will be the actuator body and the peripheral portion of the portion that will be the mirror are removed by etching. In this way, the actuator body and the mirror are formed.